New effective luminescent materials based on the Sm-doped borate glasses

¹Division of Spectroscopy of Functional Materials, Institute of Physics, University of Zielona Góra,  4a Szafrana str., 65-516 Zielona Góra, Poland

²Department of Optical Materials, Vlokh Institute of Physical Optics, 23 Dragomanov str., 79-005 Lviv, Ukraine

³Department of Spectroscopy of Laser Materials, Division of Optical Spectroscopy,  Institute of Low Temperature and Structure Research Polish Academy of Sciences, 2 Okólna str, 50-422 Wrocław, Poland

Adv. Mater. Lett., 2017, 8 (6), pp 723-734

DOI: 10.5185/amlett.2017.1436

Publication Date (Web): Apr 30, 2017

Copyright © IAAM-VBRI Press

E-mail: B.Padlyak@if.uz.zgora.pl

Abstract

The spectroscopic and radiative properties of the Sm-doped borate glasses with Li₂B₄O₇, LiKB₄O₇, CaB₄O₇, and LiCaBO₃ basic compositions as new luminescent materials have been investigated and analysed. The borate glasses of high chemical purity and optical quality, doped with Sm₂O₃ in amounts of 0.5 and 1.0 mol. % were obtained from corresponding polycrystalline compounds in the air atmosphere using standard glass synthesis technology. The spectroscopic properties of obtained Sm-doped glasses were studied using electron paramagnetic resonance (EPR), optical absorption, photoluminescence, and decay kinetics techniques. The Judd–Ofelt theory had been used for analysis of the optical absorption spectra and calculation of the phenomenological intensity parameters (Ω₂, Ω₄, Ω₆). Radiative properties such as transition probabilities (A_rad), branching ratios (β_exp and β_rad), stimulated emission cross-sections (σ_e), and radiative lifetimes (τ_rad) were estimated for ⁴G_5/2 → ⁶H_J (J = 5/2, 7/2, 9/2, and 11/2) emission transitions of the Sm³⁺ ions in the Li₂B₄O₇:Sm, CaB₄O₇:Sm, and LiCaBO₃:Sm glasses containing 1.0 mol. % Sm₂O₃. The luminescence kinetics of Sm³⁺ centres in the investigated glasses are characterised by a single exponent decay with typical lifetimes, which depend on the basic glass composition and Sm impurity concentration. Experimental lifetimes (τ_exp) have been compared with those calculated (τ_rad) and quantum efficiencies (η) of the Sm³⁺ emission transitions were estimated. The calculated high quantum efficiencies (~ 80 %) and measured high quantum yields of luminescence (~ 14 – 21 %) clearly show that the investigated glasses belong to very promising materials for luminescent and laser applications.

Keywords

Borate glasses, Sm³⁺ ions, optical absorption, luminescence spectra, Judd&ndash,Ofelt analysis, luminescence kinetics, radiative properties.